package com.hmdp.utils;

import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

@Component
public class RedisIdWorker {

    private static final long BEGIN_TIMESTAMP = 1735689600L; //开始时间戳
    private static final long COUNT_BITS = 32; //序列号位数
    private StringRedisTemplate stringRedisTemplate;
    public RedisIdWorker(StringRedisTemplate stringRedisTemplate) {
        this.stringRedisTemplate = stringRedisTemplate;
    }

    /**
     * 优惠券秒杀--redis实现全局唯一id
     * @param keyPrefix
     * @return
     */
    public long nextId(String keyPrefix) {
        //1、生成时间戳
        LocalDateTime now = LocalDateTime.now();
        long nowSecond = now.toEpochSecond(ZoneOffset.UTC);
        long timeStamp = nowSecond - BEGIN_TIMESTAMP;

        //2、生成序列号
        //2.1、获取当前日期，精确到天
        String date = now.format(DateTimeFormatter.ofPattern("yyyy-MM-dd"));
        //2.2、自增长
        long count = stringRedisTemplate.opsForValue().increment("irc:" + keyPrefix + ":" + date);

        //3、拼接时间戳和序列号，并返回
        return timeStamp << COUNT_BITS | count;
    }
}
